my name is Stian Solberg and I work on an Open Source product called Gaia Ajax, which is an Ajax UI framework for ASP.NET. It has basically much of the power that
Google Web Toolkit (which wave.google.com is built with) and the product managers behind the Wave says they couldn't have done it without a abstraction of the JavaScript development and be able to write
the application in a managed language (here Java).

With Gaia you will use the same syntax and coding as you are used to in ASP.NET, only with gaia: instead of asp:.

You can use C# or any .NET language and the result is freedom to do everything in your browser along with tiny, highly optimized ajax calls. We could demonstrate for the group at wave.codeplex.com why
Gaia Ajax would be the best foundation for building what you are doing to fully concentrate on functionality of the .NET Wave, and not struggling with browser differences and JavaScript quirks.

You can contact me at stian dot solberg at gaiaware
dot net and our web page is at http://gaiaware.net